Interference Mitigation in Wireless Communication – A Tutorial on Spread Spectrum Technology

This paper focuses on Spread Spectrum technique and its interference mitigation feature as applied in wireless communication. With spread spectrum technology it is possible to implement the transmission of multiple signals over wider ranges of spectrum without resulting to interference from other signals transmitted over the same frequencies. It does this by rejecting any received signal that does not carry the proper code. Interference rejection, one of the several features of spread spectrum technology is a difficult concept to understand. It is therefore proper to x-ray this topic in a less complex manner so that it can be well understood by those who are not mathematically grounded. In view of this a further simplified approach in presenting this subject is necessary. A tutorial approach is used to simplify this subject for better understanding and how this feature is used in Code Division Multiple Access (CDMA) systems. To show how multipath interference rejection is achieved in CDMA systems simple equations and schematics were used. The discussions cover the method of code recognition at the receiver which serves as a technique for interference mitigation. The paper helps to understand the theory of code recognition in Spread Spectrum, and thus provides answer to the question on how does interference mitigation or rejection in spread spectrum works?